[SOLVED] How to patch a kernel module

theCapitain · 04-07-2020, 03:41 AM

Hello,
I need to patch the kernel module: /lib/modules/4.4.217/kernel/drivers/media/usb/gspca/gspca_ov519.ko
using the source I’ve found here: github.com/torvalds/linux/blob/master/drivers/media/usb/gspca/ov519.c (that should add some tricks to support mi webcam).
Since I never did something like that, and I have no idea how to proceed, would someone be so kind as to show me the way step by step?
Thanks for helping.

willysr · 04-07-2020, 04:00 AM

you need to patch the kernel source and rebuild the modules again

theCapitain · 04-07-2020, 04:07 AM

Thanks for the quick reply willysr, could you show me how to do that? Really, my skills do not go beyond using upgradepkg.

Chuck56 · 04-07-2020, 06:20 AM

I recommend checking out SlackBuilds for "kmod" packages. My last public SlackBuild for a module upgrade was for kvm-kmod in the 14.0 Slackbuilds. There are other examples if you search around at SlackBuilds.org.

theCapitain · 04-07-2020, 08:22 AM

Quote:

I recommend checking out SlackBuilds for "kmod" packages

I can see that the source for your kmod’s SlackBuilds contains multiple files, including of course Makefile and configure. That make me think I cannot download only the ov519.c source file from the repository, should I download the whole gspca module? Or is it fine to use the gspca folder I have un /usr/src/ replacing ov519.c?

allend · 04-07-2020, 08:32 AM

The kernel Makefile accepts an option to build a single kernel module. From the /usr/src/linux directory:

Code:

make M=drivers/media/usb/gspca

0XBF · 04-07-2020, 08:58 AM

I've used a method similar to this post on stackoverflow to build single kernel modules:
https://stackoverflow.com/questions/...04152#44204152

You'll need the kernel source for the same version as what you're running, and you'll have to apply your patch before building the module. Once you build it you can try replacing the existing module with the newly patched one. Note that if you upgrade the kernel afterwards with slackpkg your modules will be replaced with the stock ones again.

theCapitain · 04-08-2020, 02:46 AM

Great! That was the kind of help I was asking for.
I've followed your guide. Step 9 shows:

Code:

bash-4.3# make -C . M=/root/extra
make: Entering directory '/root/linux-4.4.217'
  Building modules, stage 2.
  MODPOST 0 modules
make: Leaving directory '/root/linux-4.4.217'

After that I only have the ov519.o in the extra/ directory, the ov519.ko is missing (moreover it is called gspca_ov519.ko in my modules tree)

the Makefile I created only contains the row:

Code:

obj-y    += ov519.o

any idea?

theCapitain · 04-08-2020, 03:01 AM

I've found the way. I've modified the Makefile as follows:

Code:

obj-$(CONFIG_USB_GSPCA_OV519)    += gspca_ov519.o

gspca_ov519-objs    := ov519.o

It worked!